Hierarchical Porous Nickel Anode with Low Polarization at High Current Density

Metal anodes have attracted much interest in metal batteries because of their high theoretical capacity and outstanding electrochemical performance. However, practical applications of metal anodes are often limited by polarization effects, leading to limited reaction capacity, lower energy efficiency, and shorter cycle life. Herein, a hierarchical porous nickel (Ni) is proposed as a promising anode with extremely low polarization at a high current density and reaction capacity. This Ni anode has a large specific surface area, and fast reaction kinetics can be realized. As a result, this porous Ni anode is capable of achieving an extremely low polarization voltage of ~10 mV at 40 mA cm−2@40 mAh cm−2. In contrast, the polarization voltage of the Ni plate anode is ~100 mV at 40 mA cm−2@40 mAh cm−2. Additionally, symmetrical coin cells made in a unique way can be maintained for 800 h at 40 mA cm−2@40 mAh cm−2 and 400 h at 80 mA cm−2@80 mAh cm−2. This porous Ni anode that can achieve low polarization at a high current density/high capacity provides a new direction for developing high-performance nickel metal batteries.